Radio Base Station and User Equipment and Methods Therein

ABSTRACT

Embodiments herein include a method in a user equipment (UE) for transmitting uplink control information in time slots of a subframe over a radio channel to a radio base station. The uplink control information is comprised in a block of bits. 
     The UE maps the block of bits to a sequence of complex valued modulation symbols. The UE block spreads the sequence across Discrete Fourier Transform Spread-Orthogonal Frequency Division Multiplexing (DFTS-OFDM) symbols. This is performed by applying a spreading sequence to the sequence of complex valued modulation symbols, to achieve a block spread sequence of complex valued modulation symbols. The UE further transforms the block-spread sequence, per DFTS-OFDM symbol. This is performed by applying a matrix that depends on a DFTS-OFDM symbol index and/or slot index to the block-spread sequence. The UE also transmits the block spread sequence, as transformed, over the radio channel to the radio base station.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/134,326, which was filed on Dec. 19, 2013, which is acontinuation of U.S. patent application Ser. No. 13/119,504, which wasfiled on Mar. 17, 2011, which is a national stage application ofPCT/SE2011/050052, filed Jan. 18, 2011, and claims benefit of U.S.Provisional Application 61/295,885, filed Jan. 18, 2010, the disclosuresof each of which are incorporated herein by reference in their entirety.

TECHNICAL FIELD

Embodiments herein relate to a radio base station, a user equipment andmethods therein. In particular, embodiments herein relate totransmission of uplink control information comprised in a block of bitsover a radio channel to the radio base station.

BACKGROUND

In today's radio communications networks a number of differenttechnologies are used, such as Long Term Evolution (LTE), LTE-Advanced,3rd Generation Partnership Project (3GPP) Wideband Code DivisionMultiple Access (WCDMA), Global System for Mobilecommunications/Enhanced Data rate for GSM Evolution (GSM/EDGE),Worldwide Interoperability for Microwave Access (WiMax), and UltraMobile Broadband (UMB), just to mention a few.

Long Term Evolution (LTE) is a project within the 3rd GenerationPartnership Project (3GPP) to evolve the WCDMA standard towards thefourth generation of mobile telecommunication networks. In comparisonswith WCDMA, LTE provides increased capacity, much higher data peak ratesand significantly improved latency numbers. For example, the LTEspecifications support downlink data peak rates up to 300 Mbps, uplinkdata peak rates of up to 75 Mbit/s and radio access network round-triptimes of less than 10 ms. In addition, LTE supports scalable carrierbandwidths from 20 MHz down to 1.4 MHz and supports both FrequencyDivision Duplex (FDD) and Time Division Duplex (TDD) operation.

LTE is a Frequency Division Multiplexing technology wherein OrthogonalFrequency Division Multiplexing (OFDM) is used in a downlink (DL)transmission from a radio base station to a user equipment. SingleCarrier-Frequency Domain Multiple Access (SC-FDMA) is used in an uplink(UL) transmission from the user equipment to the radio base station.Services in LTE are supported in the packet switched domain. The SC-FDMAused in the uplink is also referred to as Discrete Fourier TransformSpread (DFTS)-OFDM.

The basic LTE downlink physical resource may thus be seen as atime-frequency grid as illustrated in FIG. 1, where each ResourceElement (RE) corresponds to one OFDM subcarrier during one OFDM symbolinterval. A symbol interval comprises a cyclic prefix (cp), which cp isa prefixing of a symbol with a repetition of the end of the symbol toact as a guard band between symbols and/or facilitate frequency domainprocessing. Frequencies f or subcarriers having a subcarrier spacing Δfare defined along an z-axis and symbols are defined along an x-axis.

In the time domain, LTE downlink transmissions are organized into radioframes of 10 ms, each radio frame comprising ten equally-sizedsubframes, #0-#9, each with a T_(subframe)=1 ms of length in time asshown in FIG. 2. Furthermore, the resource allocation in LTE istypically described in terms of resource blocks, where a resource blockcorresponds to one slot of 0.5 ms in the time domain and 12 subcarriersin the frequency domain. Resource blocks are numbered in the frequencydomain, starting with resource block 0 from one end of the systembandwidth.

Downlink transmissions are dynamically scheduled, i.e., in each subframethe base station or radio base station transmits control informationabout to which user equipments or terminals data is transmitted and uponwhich resource blocks the data is transmitted, in the current downlinksubframe. This control signaling is typically transmitted in the first1, 2, 3 or 4 OFDM symbols in each subframe. A downlink system with 3OFDM symbols used for control signaling is illustrated in FIG. 3 anddenoted as control region. The resource elements used for controlsignaling are indicated with wave-formed lines and resource elementsused for reference symbols are indicated with diagonal lines.Frequencies f or subcarriers are defined along an z-axis and symbols aredefined along an x-axis.

LTE uses hybrid-Automatic Repeat Request (ARQ), where, after receivingdownlink data in a subframe, the user equipment attempts to decode itand reports to the radio base station using uplink control signalingwhether the decoding was successful by sending an Acknowledgement (ACK)if successful decoding or a “non Acknowledgement” (NACK) if notsuccessful decoding. In case of an unsuccessful decoding attempt, theradio base station may retransmit the erroneous data.

Uplink control signaling from the user equipment or terminal to the basestation or radio base station comprises

hybrid-ARQ acknowledgements for received downlink data;

user equipment or terminal reports related to the downlink channelconditions, used as assistance for the downlink scheduling;

scheduling requests, indicating that a user equipment or terminal needsuplink resources for uplink data transmissions.

Uplink control information may be transmitted in two different ways:

on the Physical Uplink shared Channel (PUSCH). If the user equipment orterminal has been assigned resources for data transmission in thecurrent subframe, uplink control information, including hybrid-ARQacknowledgements, is transmitted together with data on the PUSCH.

on the Physical Uplink Control Channel (PUCCH). If the user equipment orterminal has not been assigned resources for data transmission in thecurrent subframe, uplink control information is transmitted separatelyon PUCCH, using resource blocks specifically assigned for that purpose.

Herein the focus is on the latter case, i.e. where Layer1/Layer2 (L1/L2)control information, exemplified by channel-status reports, hybrid-ARQacknowledgements, and scheduling requests, is transmitted in uplinkresources, i.e. in the resource blocks, specifically assigned for uplinkL1/L2 control information on the Physical Uplink Control Channel(PUCCH). Layer 1 comprises a physical layer and Layer 2 comprises thedata link layer. As illustrated in FIG. 4, PUCCH resources 41, 42 arelocated at the edges of the total available cell uplink systembandwidth. Each such resource comprises twelve “subcarriers”, i.e. itcomprises one resource block, within each of the two slots of an uplinksubframe. In order to provide frequency diversity, these frequencyresources are frequency hopping on the slot boundary, as illustrated bythe arrow, i.e. within a subframe there is one “resource” 41 comprising12 subcarriers at the upper part of the spectrum within a first slot ofthe subframe and an equally sized resource 42 at the lower part of thespectrum during a second slot of the subframe or vice versa. If moreresources are needed for the uplink L1/L2 control signaling, e.g. incase of very large overall transmission bandwidth supporting a largenumber of users, additional resource blocks may be assigned next to thepreviously assigned resource blocks. Frequencies f or subcarriers aredefined along an z-axis and symbols are defined along an x-axis.

The reasons for locating the PUCCH resources at the edges of the overallavailable spectrum are:

Together with the frequency hopping described above, the location of thePUCCH resources at the edges of the overall available spectrum maximizesthe frequency diversity experienced by the control signaling.

Assigning uplink resources for the PUCCH at other positions within thespectrum, i.e. not at the edges, would have fragmented the uplinkspectrum, making it impossible to assign very wide transmissionbandwidths to single mobile user equipment or terminal and still retainthe single-carrier property of the uplink transmission.

The bandwidth of one resource block during one subframe is too large forthe control signaling needs of a single user equipment or terminal.Therefore, to efficiently exploit the resources set aside for controlsignaling, multiple user equipments or terminals may share the sameresource block. This is done by assigning the different user equipmentsor terminals different orthogonal phase rotations of a cell-specificlength-12 frequency-domain sequence.

The resource used by a PUCCH is therefore not only specified in thetime-frequency domain by the resource-block pair, but also by the phaserotation applied. Similarly to the case of reference signals, there areup to twelve different phase rotations specified, providing up to twelvedifferent orthogonal sequences from each cell-specific sequence.However, in the case of frequency-selective channels, not all the twelvephase rotations may be used if orthogonality is to be retained.Typically, up to six rotations are considered usable in a cell.

As mentioned above, uplink L1/L2 control signaling includes hybrid-ARQacknowledgements, channel-status reports and scheduling requests.Different combinations of these types of messages are possible, usingone of two available PUCCH formats, capable of carrying different numberof bits.

PUCCH format 1.There are actually three formats, 1, 1a, and 1b in theLTE specifications, although herein they are all referred to as format 1for simplicity.

PUCCH format 1 is used for hybrid-ARQ acknowledgements and schedulingrequests. It is capable of carrying up to two information bits inaddition to Discontinuous Transmission (DTX). If no informationtransmission was detected in the downlink, no acknowledgement isgenerated, also known as DTX. Hence, there are 3 or 5 differentcombinations, depending on whether MIMO was used on the downlink or not.This is illustrated in FIG. 5. In col 51 the combination index isdenoted, in col 52 the ARQ information sent when no MIMO is used isdisclosed, and in col 53 the ARQ information when MIMO is used when afirst transport block and a second transport block are received isshown.

PUCCH format 1 uses the same structure in the two slots of a subframe,as illustrated in FIG. 6. For transmission of a hybrid-ARQacknowledgement (ACK), the single hybrid-ARQ acknowledgement bit is usedto generate a Binary Phase-Shift Keying (BPSK) symbol, in case ofdownlink spatial multiplexing the two acknowledgement bits are used togenerate a Quadrature Phase Shift Keying (QPSK) symbol. For a schedulingrequest, on the other hand, the BPSK/QPSK symbol is replaced by aconstellation point treated as negative acknowledgement at the radiobase station or evolved NodeB (eNodeB). Each BPSK/QPSK symbol ismultiplied with a length-12 phase rotated sequence. These are thenweighted with a length-4 sequence before transformed in an IFFT process.Phase shifts vary on SC-FDMA or DFTS-OFDM symbol level. The referencesymbols (RS) are weighted with a length-3 sequence. The modulationsymbol is then used to generate the signal to be transmitted in each ofthe two PUCCH slots. BPSK modulation symbols, QPSK modulation symbols,and complex valued modulation symbols are examples of modulationsymbols.

For PUCCH format 2, there are also three variants in the LTEspecifications, formats 2, 2a and 2b, where the last two formats areused for simultaneous transmission of hybrid-ARQ acknowledgements asdiscussed later in this section. However, for simplicity, they are allreferred to as format 2 herein.

Channel-status reports are used to provide the radio base station oreNodeB with an estimate of the channel properties at the user equipmentor terminal in order to aid channel-dependent scheduling. Achannel-status report comprises multiple bits per subframe. PUCCH format1, which is capable of at most two bits of information per subframe, canobviously not be used for this purpose. Transmission of channel-statusreports on the PUCCH is instead handled by PUCCH format 2, which iscapable of multiple information bits per subframe.

PUCCH format 2, illustrated for normal cyclic prefix in FIG. 7, is basedon a phase rotation of the same cell-specific sequence as format 1, i.e.lenghth-12 phase rotated sequence that is varying per SC-FDMA orDFTS-OFDM symbol. The information bits are block coded, QPSK modulated,each QPSK symbol b0-b9 from the coding is multiplied by the phaserotated length-12 sequence and all SC-FDMA or DFTS-OFDM symbols arefinally IFFT processed before transmitted.

In order to meet the upcoming International Mobile Telecommunications(IMT) -Advanced requirements, 3GPP is currently standardizing LTERelease 10 also known as LTE-Advanced. One property of Release 10 is thesupport of bandwidths larger than 20 MHz while still providing backwardscompatibility with Release 8. This is achieved by aggregating multiplecomponent carriers, each of which can be Release 8 compatible, to form alarger overall bandwidth to a Release 10 user equipment. This isillustrated in FIG. 8, where five 20 MHz are aggregated into 100 MHz.

In essence, each of the component carriers in FIG. 8 is separatelyprocessed. For example, hybrid ARQ is operated separately on eachcomponent carrier, as illustrated in FIG. 9. For the operation ofhybrid-ARQ, acknowledgements informing the transmitter on whether thereception of a transport block was successful or not is required. Astraightforward way of realizing this is to transmit multipleacknowledgement messages, one per component carrier. In case of spatialmultiplexing, an acknowledgement message would correspond to two bits asthere are two transport blocks on a component carrier in this casealready in the first release of LTE. In absence of spatial multiplexing,an acknowledgement message is a single bit as there is only a singletransport block per component carrier. Each flow F1-Fi illustrates adata flow to the same user. Radio Link control (RLC) for each receiveddata flow is performed on the RLC layer. In the Medium Access Control(MAC) layer MAC multiplexing and HARQ processing is performed on thedata flow. In the physical (PHY) layer the coding and OFDM modulation ofthe data flow is performed.

Transmitting multiple hybrid-ARQ acknowledgement messages, one percomponent carrier, may in some situations be troublesome. If the currentLTE Frequency Division Multiplex (FDM) uplink control signalingstructures are to be reused, at most two bits of information may be sentback to the radio base station or eNodeB using PUCCH format 1.

One possibility is to bundle multiple acknowledgement bits into a singlemessage. For example, ACK could be signaled only if all transport blockson all component carriers are correctly received in a given subframe,otherwise a NACK is fed back. A drawback of this is that some transportblocks might be retransmitted even if they were correctly received,which could reduce performance of the system.

Introducing a multi-bit hybrid-ARQ acknowledgement format is analternative solution. However, in case of multiple downlink componentcarriers, the number of acknowledgement bits in the uplink may becomequite large. For example, with five component carriers, each using MIMO,there are 5⁵ different combinations, keeping in mind that the DTX ispreferably accounted for as well, requiring at least log₂(5⁵)≈11.6 bits.The situation can get even worse in Time Division Duplex (TDD), wheremultiple downlink subframes may need to be acknowledged in a singleuplink subframe. For example, in a TDD configuration with 4 downlinksubframes and 1 plink subframe per 5 ms, there are 5^(5·4) combinations,corresponding to more than 46 bits of information.

Currently, there is no PUCCH format in LTE specified capable of carryingsuch a large number of bits.

SUMMARY

An object of embodiments herein is to provide a mechanism that enableshigh transmission performance in a radio communications network in anefficient manner.

According to a first aspect of embodiments herein the object is achievedby a method in a user equipment for transmitting uplink controlinformation in time slots in a subframe over a radio channel to a radiobase station. The radio channel is arranged to carry uplink controlinformation and the user equipment and radio base station are comprisedin a radio communications network. The uplink control information iscomprised in a block of bits.

The user equipment maps the block of bits to a sequence of complexvalued modulation symbols. The user equipment also block spreads thesequence of complex valued modulation symbols across Discrete FourierTransform Spread-Orthogonal Frequency Division Multiplexing (DFTS-OFDM)symbols. This is performed by applying a spreading sequence to thesequence of complex valued modulation symbols, to achieve a block spreadsequence of complex valued modulation symbols. The user equipmentfurther transforms the block-spread sequence of complex valuedmodulation symbols per DFTS-OFDM symbol. This is performed by applying amatrix that depends on a DFTS-OFDM symbol index and/or slot index to theblock-spread sequence of complex valued modulation symbols. The userequipment also transmits the block spread sequence of complex valuedmodulation symbols that has been transformed over the radio channel tothe radio base station.

According to another aspect of embodiments herein the object is achievedby a user equipment for transmitting uplink control information in timeslots in a subframe over a radio channel to a radio base station. Theradio channel is arranged to carry uplink control information, and theuplink control information is comprised in a block of bits.

The user equipment comprises a mapping circuit configured to map theblock of bits to a sequence of complex valued modulation symbols. Also,the user equipment comprises a block spreading circuit configured toblock spread the sequence of complex valued modulation symbols acrossDFTS-OFDM symbols by applying a spreading sequence to the sequence ofcomplex valued modulation symbols, to achieve a block spread sequence ofcomplex valued modulation symbols. Furthermore, the user equipmentcomprises a transforming circuit configured to transform theblock-spread sequence of complex valued modulation symbols per DFTS-OFDMsymbol. This is done by applying a matrix that depends on a DFTS-OFDMsymbol index and/or slot index to the block-spread sequence of complexvalued modulation symbols. The user equipment also comprises atransmitter configured to transmit the block spread sequence of complexvalued modulation symbols that has been transformed over the radiochannel to the radio base station.

According to another aspect of embodiments herein the object is achievedby a method in a radio base station for receiving uplink controlinformation in time slots in a subframe over a radio channel from a userequipment. The radio channel is arranged to carry uplink controlinformation and the uplink control information is comprised in a blockof bits. The user equipment and radio base station are comprised in aradio communications network.

The radio base station receives a sequence of complex valued modulationsymbols. The radio base station also OFDM demodulates the sequence ofcomplex valued modulation symbols. The radio base station alsotransforms, per DFTS-OFDM symbol, the sequence of complex valuedmodulation symbols that has been OFDM demodulated by applying a matrixthat depends on a DFTS-OFDM symbol index and/or slot index to the OFDMdemodulated sequence of complex valued modulation symbols.

The radio base station further despreads the sequence of complex valuedmodulation symbols that has been OFDM demodulated and transformed with adespreading sequence. The radio base station also maps the despreadsequence of complex valued modulation symbols that has been OFDMdemodulated and transformed, to the block of bits.

According to another aspect of embodiments herein the object is achievedby a radio base station for receiving uplink control information in timeslots in a subframe over a radio channel from a user equipment. Theradio channel is arranged to carry uplink control information, and theuplink control information is comprised in a block of bits. The radiobase station comprises a receiver configured to receive a sequence ofcomplex valued modulation symbols. The radio base station also comprisesan OFDM demodulating circuit configured to OFDM demodulate the sequenceof complex valued modulation symbols. The radio base station furthercomprises a transforming circuit configured to transform, per DFTS-OFDMsymbol, the sequence of complex valued modulation symbols that has beenOFDM demodulated by applying a matrix that depends on a DFTS-OFDM symbolindex and/or slot index to the OFDM demodulated sequence of complexvalued modulation symbols. The radio base station also comprises a blockdespreading circuit configured to block despread the sequence of complexvalued modulation symbols that has been OFDM demodulated andtransformed, with a despreading sequence. Furthermore, the radio basestation comprises a mapping circuit configured to map the despreadsequence of complex valued modulation symbols that has been OFDMdemodulated and transformed, to the block of bits.

Thus, the inter-cell interference is reduced since the matrix ormatrices transforms the block spread sequence of complex valuedmodulation symbols per DFTS-OFDM symbol and thereby increasesinterference suppression.

According to another aspect of embodiments herein the object is achievedby a method in a terminal for transmitting uplink control information ina slot in a subframe over a channel to a base station in a wirelesscommunication system. The uplink control information is comprised in acode word. The terminal maps the code word to modulation symbols. Theterminal block spreads the modulation symbols across DFTS-OFDM symbolsby repeating the modulation symbols for each DFTS-OFDM symbol andapplying a block spreading sequence of weight factors to the repeatedmodulation symbols to achieve a respective weighted copy of themodulation symbols for each DFTS-OFDM symbol. The terminal thentransforms, for each DFTS-OFDM symbol, the respective weighted copy ofthe modulation symbols by applying a matrix that depends on a DFTS-OFDMsymbol index and/or slot index to the respective weighted copy of themodulation symbols. The terminal then transmits, on or within eachDFTS-OFDM symbol, the respective weighted copy of the modulation symbolsthat has been transformed to the base station.

In some embodiments herein, a transmission format is provided wherein acode word or block of bits corresponding to uplink control informationfrom all configured or activated component carriers of a single user ismapped to modulation symbols such as a sequence of complex valuedmodulation symbols and block spread over DFTS-OFDM symbols using aspreading sequence. The symbol sequence within one DFTS-OFDM symbol isthen transformed and transmitted within the one DFTS-OFDM symbol.Multiplexing of users is enabled with block spreading, i.e. the samesignal or symbol sequence is spread across all DFTS-OFDM symbols withinone slot or subframe and the transformation per DFTS-OFDM symbol reducesthe inter-cell interference.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described in more detail in relation to theenclosed drawings, in which:

FIG. 1 is a block diagram depicting resources in a frequency-time grid,

FIG. 2 is a block diagram depicting a LTE time-domain structure of aradio frame,

FIG. 3 is a block diagram depicting symbols distributed over a downlinksubframe,

FIG. 4 is a block diagram depicting Uplink L1/L2 control signallingtransmission on PUCCH,

FIG. 5 is a table defining combinations of HARQ information,

FIG. 6 is a block diagram of PUCCH format 1 with normal length of cyclicprefix,

FIG. 7 is a block diagram of PUCCH format 2 with normal length of cyclicprefix,

FIG. 8 is a block diagram depicting carrier aggregation,

FIG. 9 is a block diagram depicting RLC/MAC and PHY layers for carrieraggregation,

FIG. 10 is a block diagram depicting a radio communications network,

FIG. 11 is a block diagram depicting a process in a user equipment,

FIG. 12 is a block diagram depicting a process in a user equipment,

FIG. 13 is a block diagram depicting a process in a user equipment,

FIG. 14 is a block diagram depicting a process in a user equipment,

FIG. 15 is a block diagram depicting a process in a user equipment,

FIG. 16 is a block diagram depicting a process in a user equipment,

FIG. 17 is a block diagram depicting a process in a user equipment,

FIG. 18 is a block diagram depicting a process in a user equipment,

FIG. 19 is a block diagram depicting a process in a user equipment,

FIG. 20 is a schematic flowchart of a process in a user equipment,

FIG. 21 is a block diagram depicting a user equipment,

FIG. 22 is a schematic flowchart of a process in a radio base station,and

FIG. 23 is a block diagram depicting a radio base station.

DETAILED DESCRIPTION

FIG. 10 discloses a schematic radio communication network, also referredto as a wireless communication system, according to a radio accesstechnology such as Long Term Evolution (LTE), LTE-Advanced, 3rdGeneration Partnership Project (3GPP) Wideband Code Division MultipleAccess (WCDMA), Global System for Mobile communications/Enhanced Datarate for GSM Evolution (GSM/EDGE), Worldwide Interoperability forMicrowave Access (WiMax), or Ultra Mobile Broadband (UMB), just tomention a few possible implementations.

The radio communications network comprises a user equipment 10, alsoreferred to as a terminal 10, and a radio base station 12. The radiobase station 12 serves the user equipment 10 in a cell 14 by providingradio coverage over a geographical area. The radio base station 12 istransmitting data in a downlink (DL) transmission to the user equipment10 and the user equipment 10 is transmitting data in an uplink (UL)transmission to the radio base station 12. The UL transmission mayefficiently be generated by the use of an Inverse Fast Fourier Transform(IFFT) process at the user equipment 10 and then demodulated at theradio base station 12 by the use of a Fast Fourier Transform (FFT)process.

It should here be noted that the radio base station 12 may also bereferred to as e.g. a NodeB, an evolved Node B (eNB, eNode B), a basestation, a base transceiver station, Access Point Base Station, basestation router, or any other network unit capable of communicating witha user equipment within the cell served by the radio base station 12,depending e.g. on the radio access technology and terminology used. Theuser equipment 10 may be represented by a terminal e.g. a wirelesscommunication user equipment, a mobile cellular phone, a PersonalDigital Assistant (PDA), a wireless platform, a laptop, a computer orany other kind of device capable to communicate wirelessly with theradio base station 12.

The radio base station 12 transmits control information about to whichuser equipment data is transmitted and upon which resource blocks thedata is transmitted. The user equipment 10 tries to decode the controlinformation and data and reports to the radio base station 12 usinguplink control signaling whether decoding of data was successful inwhich case an Acknowledgement (ACK) is transmitted, or not successful,in which case a Non-Acknowledgement (NACK, NAK) is transmitted.

According to embodiments herein the user equipment 10 is arranged totransmit a block of bits corresponding to the uplink control informationin slots, i e timeslots, in a subframe over a channel, i e a radiochannel, to the radio base station 12. The block of bits may compriseACK and/or NACK, jointly encoded. The channel may be a Physical UplinkControl Channel (PUCCH), which is a radio channel arranged to carryuplink control information. The block of bits may also be referred to asnumber of bits, code word, encoded bits, information bits, an ACK/NACKsequence or similar.

The user equipment 10 maps the block of bits to modulation symbols, i eto a sequence of complex valued modulation symbols. This mapping may bea QPSK mapping wherein the resulting QPSK modulation symbol iscomplex-valued, where one of the two bits in each QPSK modulation symbolrepresents the real part, also referred to as an I channel, of themodulation symbol and the other bit the imaginary part, also referred toas a Q channel, of the modulation symbol. The modulation symbols may bereferred to as complex valued modulation symbols, QPSK symbols, BPSKsymbols or similar.

The user equipment 10 then block spreads the sequence of complex valuedmodulation symbols with a spreading sequence, such as an orthogonalsequence. For example, the same signal or block of bits that has beenmapped to the complex valued modulations symbols may be spread acrossall DFTS-OFDM symbols in a set of DFTS-OFDM symbols by applying thespreading sequence to the sequence of complex valued modulations symbolsrepresenting the signal or block of bits. The block spread sequence ofcomplex valued modulation symbols may thereby be divided into parts orsegments wherein each segment or part of the block spread sequence ofcomplex valued modulation symbols correspond to or is allocated to oneDFTS-OFDM symbol out of the set of DFTS-OFDM symbols, i.e. there is aone to one correspondence between the segments or parts and theDFTS-OFDM symbols. DFTS-OFDM symbols are also referred to as SC-FDMAsymbols. SC-FDMA may be seen as normal OFDM with a DFT-based precoding.

According to embodiments herein, the user equipment 10 then transformsor precodes the block-spread sequence of complex valued modulationsymbols per DFTS-OFDM symbol with a matrix that depends on a DFTS-OFDMsymbol index and/or slot index. Thus, each segment or part of the blockspread sequence of complex valued modulation symbols which correspondsto or is allocated to a DFTS-OFDM symbol is transformed separately byapplying the matrix to this segment or part of the block spread sequenceof complex valued modulation symbols. The matrix may be a general matrixthat comprises a DFT matrix, for example, a DFT matrix which iscyclically shifted, wherein the amount of cyclic shift varies with theDFTS-OFDM symbol index and/or slot index. By transforming the blockspread sequence of complex valued modulation symbols this way, theinter-cell interference is reduced. A slot comprises several DFTS-OFDMsymbols, i.e. each slot is associated with multiple matrices, one foreach DFTS-OFDM symbol. The slot index indicates the time slot withinwhich the matrix or matrices is to be applied. The DFTS-OFDM symbolindex indicates the DFTS-OFDM symbol, and thereby the segment or part ofthe block spread sequence of complex valued modulation symbols, to whichthe matrix is to be applied.

The user equipment 10 then transmits the block spread sequence ofcomplex valued modulation symbols that has been transformed. Forexample, the user equipment 10 may further OFDM modulate and transmiteach transformed or precoded segment or part of the block spreadsequence within the time duration of one DFTS-OFDM symbol, i e theDFTS-OFDM symbol that corresponds to the respective segment or part ofthe block spread sequence of complex valued modulation symbols. Theprocess may be referred to as transformed/precoded OFDM-modulation.

In a variation of this embodiment the sequence of complex valuedmodulation symbols may be split into multiple parts and each part of thesequence of complex valued modulation symbols may be transmitted in atime slot.

Some embodiments herein may relate to ACK/NACK transmission on PUCCH ina radio communications network employing aggregation of multiple cells,i.e. component carriers, to provide support of bandwidths larger than asingle carrier while still providing backwards compatibility withprevious technologies. In such a radio communications network a PUCCHformat is provided, according to embodiments herein, that is capable ofcarrying a larger number of bits than provided by existing PUCCHformats, so as to enable ACK/NACK signaling for each of the multiplecomponent carriers.

Embodiments herein enable the high payload PUCCH transmissions requiredfor such signalling by providing a block spread DFTS-OFDM transmissionformat. According to this format all ACK/NACK information from allcomponent carriers of a single user equipment are jointly encoded in acode word. This code word, corresponding to the block of bits of uplinkcontrol information, may in some embodiments then be scrambled tomitigate inter-cell interference and mapped onto symbols such as thesequence of complex valued modulation symbols. Multiplexing of userequipments is enabled with block spreading, i.e. the same signal in formof the code word, possibly scrambled with a different sequence, or inform of the symbols if the codeword has been mapped to symbols prior tothe block spreading, is spread or repeated across all DFTS-OFDM symbolsof a slot or subframe but the symbols are weighted with a differentscalar or weight factor from a spreading sequence for each DFTS-OFDMsymbol within the subframe or time slot. The sequence of symbols of eachDFTS-OFDM symbol is then transformed or precoded with the matrix, e g amodified precoding matrix, and transmitted within the time duration ofone DFTS-OFDM symbol. To mitigate interference even further the matrixof the modified DFTS-OFDM modulator is modified in a pseudo random way,e.g. by permutation of matrix elements. The transformation or precodingmay be a modified DFTs-OFDM modulation, where the DFT operation iscombined with a cyclic shift operation or a scrambling operation.

Embodiments herein provide a format, referred to as PUCCH format 3,which provides flexibility in that some solutions may be adapted to therequired increasing payload of uplink control information. It alsointroduces means to improve inter-cell interference suppression. Thesemeans are either or in combination, scrambling with a scrambling code,selection of the matrix, or cyclic shifting of matrix elements with acyclic shift pattern. The selection of the scrambling code and/or cyclicshift pattern may depend on cell ID and/or DFTS-OFDMsymbol/slot/subframe/radio frame number in a random fashion to randomizeinter-cell interference. Furthermore, the format or structure allowstrading payload and/or coding gain and/or inter-cell interferencesuppression against multiplexing capacity. A low code rate means manycoded bits relative to information bits and if the coded bits arescrambled, the longer the scrambled sequence the better inter-cellinterference suppression. The length of the spreading sequencedetermines multiplexing capacity.

FIG. 11 together with FIG. 12 depicts one embodiment of the process in auser equipment 10 for block spreading the sequence of complex valuedmodulation symbols. FIG. 11 shows how an ACK/NACK sequence a, which isan example of a block of bits corresponding to uplink controlinformation, is transmitted within one DFTS-OFDM symbol. The sequence arepresents ACK/NACKs from all aggregated component carriers.Alternatively, the individual bits may also present a logical ANDconnection of individual ACK/NACK bits. This sequence a may not onlyrepresent ACK/NACKs, but Discontinuous transmission (DTX) states may beencoded as well, e.g. if no scheduling assignment has been received forcertain component carriers.

In a first step the sequence a may be encoded in an error correctioncoding module 111 to make it more robust against transmission errors. Anerror correction coding scheme used may be block codes, convolutioncodes, etc. The error correction coding module 111 may possibly alsocomprise an interleaver functionality arranging the block of bits sothat errors may occur in a more uniformly distributed manner to increasethe performance.

In order to randomize neighbor cell interference, cell specificscrambling with a code c may be applied in a scrambling module resultingin a scrambled sequence, i e scrambled block of bits. The scrambledsequence is then mapped to modulation symbols, using QPSK for example,in a symbol mapping module 112 resulting in a sequence of complex valuedmodulation symbols x and modulated and transmitted with a DFTS-OFDMmodulator 113 resulting in the sequence v of symbols for transmission.The sequence v is a digital signal, so it may be fed into a Digital toAnalogue converter, modulated to radio frequency, amplified, fed intoantenna and then transmitted.

The DFTS-OFDM modulator 113 is a modified DFTS-OFDM modulator thatcomprises a matrix G 114 and may also comprise an IFFT module 115 and acyclic prefix generator 116. Thus, the sequence v is transmitted over aDFTS-OFDM symbol or within a DFTS-OFDM symbol duration. However, toenable multiplexing of different users or user equipments, the block ofbits is to be transmitted over several DFTS-OFDM symbols to the radiobase station 12. The matrix G 114 comprises matrix elements, and thematrix may correspond to a DFT operation together with a cyclic shiftoperation of rows or columns of matrix elements, or correspond to a DFToperation together with a scrambling operation of the matrix elements.

For example, the symbol mapping module 112 maps the block of bits onto asequence of complex valued modulation symbols, x. The block spreadsequence of complex valued modulation symbols [w(0)x, w(1)x, w(2)x, . .. , w(K−1)x] is obtained after block-spreading where w=[w(0), w(1),w(2), . . . , w(K−1)] is a spreading sequence of scalars or weightfactors, which spreading sequence may in some embodiments comprise anorthogonal sequence. The modified DFTS-OFDM modulation is then doneseparately for each weighted copy or instance of the modulation symbolsw(0)x, w(1)x, w(2)x, . . . , w(K−1)x. The transmission is also doneseparately, e.g. OFDM (precoded(w(0)x)), OFDM (precoded(w(1)x)), etc.are performed. Thus, pre-coding and transmission may be done so that oneweighted copy or instance of the modulation symbols w(k)x is pre-codedand transmitted in each DFTS-OFDM symbol, for k=0, . . . , K−1 where Kis the number of DFTS_OFDM symbols over which the modulation symbols areblock spread. The spreading sequence, e.g. an orthogonal sequence,provides separation among user equipments, or more specifically, amonguplink transmissions made by different user equipments.

It should also be understood that if no frequency hopping is applied,the above-outlined solutions apply to a subframe, with parametersaccordingly adapted. The number of available DFTS-OFDM symbols could inthis case be 12, assuming 2 DFTS-OFDM symbols reserved for referencesignals.

If frequency hopping is enabled, the above-outlined solution may beapplied to each slot, possibly with different scrambling codes andspreading sequences. In this case the same payload would be transmittedin both slots. Alternatively, the scrambled sequence or the modulationsymbols, i e the sequence of complex valued modulation symbols isdivided into two parts and a first part is transmitted in a first slotand a second part in a second slot. In principle even the block of bitsa could be split and the first part could be transmitted in the firstslot and the second part in the second slot. However, this is lesspreferable since in this case the block of bits processed andtransmitted in each slot is smaller, e g half of the size before thesplit, resulting in reduced coding gain.

FIG. 12 shows an embodiment wherein the signal or block of bits is blockspread. The processing chain comprises the error correction codingmodule 111. In the simplest case the same signal or block of bits, isblock spread i.e. repeated several times, and mapped to modulationsymbols, i e a sequence of complex valued modulation symbols, and eachcopy or instance of the modulation symbols is weighted by a scalar w[k],also referred to as a weight factor from a spreading sequence. It shouldbe noted that the mapping may occur before the block spreading. If wehave K DFTS-OFDM symbols the spreading sequence has length K, i.e. w[k],k=0, 1, . . . K−1, K orthogonal spreading sequences may then beconstructed and thus K users may be multiplexed. Thus, these Korthogonal sequences are used in the block spreading of the modulationsymbols, i e the sequence of complex valued modulation symbols. This isshown in FIG. 12 where each box labeled Mod1-ModK comprises the modules112-116 according to FIG. 11. Equivalent implementations allowapplication of the weight factor at other positions anywhere after thesymbol mapping module 112 as illustrated in FIG. 12 where a weightfactor w[0]-w[K−1] is applied to respective v sequence after theDFTS-OFDM modulator 113 of the respective process chains for DFTS-OFDMsymbols 0 . . . K−1. Further, it is equivalent to map first the block ofbits to modulation symbols, e g complex valued modulation symbols andthen repeat the modulation symbols and to repeat the block of bits andthen map each repeated block of bits to modulation symbols.

In an alternative setup the signal or block of bits transmitted in the KDFTS-OFDM symbols is not a copy, if ignoring the scaling of the symbolsby w[k], but each block Mod1-ModK in FIG. 12 actually performsscrambling with a different scrambling sequence. Otherwise FIG. 11 isstill valid. In this case respective scrambling sequence may depend inaddition to the cell ID also on DFTS-OFDM symbol/slot/subframe/radioframe number. Scrambling, and especially that the scrambling sequencemay depend on cell ID and/or DFTS-OFDM/slot/subframe/radio frame number,provides better inter-cell interference randomization and mitigationthan state-of-the-art DFTS-OFDM PUCCH transmissions.

Assuming, for example, one reference symbol, also denoted referencesignal, per slot, K could be six, assuming normal cyclic prefix, in LTE.Alternatively, if no frequency hopping is used K could be 12 assumingone reference signal per slot. The exact design of reference signals isnot further discussed.

Depending on the number of allocated resource blocks in the DFTS-OFDMmodulator 113 the number of coded bits and thus the code rate and/orpayload size, length of ACK/NACK sequence or block of bits a, may becontrolled. For example, if only a single resource block is allocated infrequency domain 24 coded bits are available per DFTS-OFDM symbol,assuming QPSK symbols. If this is not sufficient, the number ofallocated resource blocks may be increased. More coded bits also allowfor a longer scrambling code c resulting in higher scrambling gain.

It is worthwhile to mention that the proposed scheme allows multiplexingof users with different resource block allocations. In FIG. 13 anexample is provided where three user equipments are multiplexed. Thefirst user equipment 10 requires a higher ACK/NACK payload and occupiestherefore two resource blocks. For the remaining two user equipments itis sufficient with one resource block each and these are FrequencyDivision Multiplexing (FDM) multiplexed. Since the user equipments areFDM multiplexed the user equipments may reuse the same spreadingsequence, but of course they may also use different spreading sequences.In this example the spreading factor is 4. The user equipment 10allocating two resource blocks uses the spreading code [1 −1 1 −1]resulting in block spread sequences of complex valued modulation symbolsover DFTS-OFDM symbols denoted as 121-124. The remaining user equipmentsuse spreading code [1 1 1 1] resulting in block spread sequences ofcomplex valued modulation symbols over DFTS-OFDM symbols denoted as131-134 for a second user equipment and as 135-138 for a third userequipment.

FIG. 14 is a block diagram according to an embodiment depicting aprocessing chain for transmission of uplink control information for oneDFTS-OFDM symbol such as a transmitter in the user equipment 10. Theuser equipment 10 may comprise the error correction coding module 111,wherein the block of bits a may be encoded to make it more robustagainst transmission errors. In order to randomize neighbor cellinterference cell specific scrambling with code c may be appliedresulting in a scrambled sequence. The scrambled sequence may then bemapped onto modulation symbols, i e a sequence of complex valuedmodulation symbols in the symbol mapping module 112, which is then blockspread with a spreading sequence (not shown). The user equipment 10transforms, e.g. precodes, per DFTS-OFDM symbol, the block-spreadsequence of complex valued modulation symbols in the DFTS-OFDM modulator113 with the matrix G 114 that depends on the DFTS-OFDM symbol indexand/or slot index. In the illustrated example, the matrix G 114corresponds to a Discrete Fourier Transformation (DFT) operation 141together with a cyclic shift operation 142 of rows or columns. The userequipment 10 may also comprise the IFFT module 115 and the cyclic prefixgenerator 116. Thus, the block spread sequence of complex valuedmodulation symbols is modulated and transmitted over the DFTS-OFDMsymbol or within one DFTS-OFDM symbol duration. However, to enablemultiplexing of different users, the error correction encoded block ofbits is to be transmitted over several DFTS-OFDM symbols to the radiobase station 12.

A variation of the above embodiment is where the scrambled sequence isnot mapped onto one DFTS-OFDM symbol but onto several DFTS-OFDM symbols.FIG. 15 shows an example where a scrambled block of bits s istransmitted over two DFTS-OFDM symbols, or over the time duration of twoDFTS-OFDM symbols. In this example a 48 bit long scrambled sequence orblock of bits s is mapped to 24=2×12 QPSK symbols and transmitted in twoDFTS-OFDM symbols, assuming one resource block allocation and eachDFTS-OFDM symbol carrying 12 symbols. The block of bits a may beprocessed in an error correction coding module 151, which may correspondto the error correction coding module 111 in FIG. 11. In order torandomize neighbor cell interference, cell specific scrambling with acode c in a bit scrambling module 152 may be applied resulting in ascrambled sequence s, i e a scrambled block of bits. The scrambledsequence s is spread over or divided on two different DFTS-OFDM symbols.The first half of s is then mapped to symbols, using QPSK, for example,in a first symbol mapping module 153 and modulated and transmitted witha first modified DFTS-OFDM modulator. The first modified DFTS-OFDMmodulator comprises a first precoding matrix G 154 and may also comprisea first IFFT module 155 and a first cyclic prefix generator 156.

The second half of s is then mapped to symbols, e g to complex valuedmodulation symbols, using QPSK, for example, in a second symbol mappingmodule 153′ and modulated and transmitted with a second modifiedDFTS-OFDM modulator. The second modified DFTS-OFDM modulator comprises asecond precoding matrix G 154′ and may also comprise a second IFFTmodule 155′ and a second cyclic prefix generator 156′.

Thus, the first half the block of bits is transmitted over the firstDFTS-OFDM symbol and the second half the block of bits is transmittedover the second DFTS-OFDM symbol. However, to enable multiplexing ofdifferent users, the error correction encoded scrambled block of bits sis to be transmitted over several DFTS-OFDM symbols to the radio basestation 12.

An embodiment of an accordingly modified block spreading process isdepicted in FIG. 16. In this example block spreading in case that thescrambled block of bits s is transmitted over two DFTS-OFDM symbols isshown. Each block “Mod” comprises the arrangement shown in FIG. 15,excluding error correction coding functionality. This variation enableshigher payloads and scrambling gain compared to the base line case ofFIG. 11. However, the price to be paid is reduced multiplexing capacity.If we assume K DFTS-OFDM symbols are available for transmission, and useL of them for one instance of the scrambled block of bits, the length ofthe spreading code or spreading sequence—and thus the multiplexingcapacity—reduces to K/L. In this example the multiplexing capacity isreduced by a factor of 2 compared to the case when the scrambled blockof bits s is modulated and transmitted over one DFTS-OFDM symbol. Theblock of bits corresponding to uplink information, such as ACK/NACKs, isprocessed in an error correction coding module 161, which may correspondto the error correction coding module 111 in FIG. 11. A number ofmodules Mod1-ModK/2 in FIG. 16 performs scrambling with a differentscrambling sequence, where a weight factor w[0]-w[(K/2)−1] is applied tothe respective block spread modulation symbols, i e the respective blockspread sequence of complex valued modulation symbols after the modulesMod1-ModK/2.

In another embodiment, in which the order of the scrambling operationand the symbol mapping is performed are changed according to FIG. 17.Here the scrambling is applied on symbol level rather than on bit level,which means that the symbol mapping is performed before the symbolscrambling. The scrambling code {tilde over (c)} may depend on the cellID as well as on DFTS-OFDM symbol index/slot/subframe/radio framenumber. The user equipment 10 may herein comprise an error correctioncoding module 171, wherein the sequence or block of bits a may beencoded to make it more robust against transmission errors. The errorcorrection coding module 171 may correspond to the error correctioncoding module 111 in FIG. 11. The block of bits is then mapped ontomodulation symbols, i e a sequence of complex valued modulation symbolsin a symbol mapping module 172. In order to randomize neighbor cellinterference, cell specific scrambling with code {tilde over (c)} may beapplied to the symbols in a symbol scrambling module 173, resulting in ascrambled sequence s′. The scrambled sequence is then discrete Fouriertransformed in a DFT module 174. The symbol scrambling module 173 andDFT module 174 may be comprised in the matrix G 114. Thus, the userequipment 10 then transforms e.g. precodes, per DFTS-OFDM symbol, theblock-spread modulation symbols, i e the block spread sequence ofcomplex valued modulation symbols, with the matrix G 114 that depends ona DFTS-OFDM symbol index and/or slot index. The user equipment 10 mayalso comprise an IFFT module 175 and a cyclic prefix generator 176.Thus, the block spread modulation symbols, i e the block spread sequenceof complex valued modulation symbols, is transmitted over the DFTS-OFDMsymbol or within one DFTS-OFDM symbol duration. However, to enablemultiplexing of different users, the block of bits is to be transmittedover several DFTS-OFDM symbols to the radio base station 12.

The scrambling operation may in some embodiments mathematically bedescribed by multiplication with a diagonal matrix C which diagonalelements are constituted by the elements of the scrambling code {tildeover (c)}, wherein {tilde over (c)} is the scrambling sequence on symbollevel. The subsequent DFT operation may be described by DFT matrix F.Using this notation the combined operation may for these illustratedexamples be expressed by the matrix G=FC. The scrambling and DFToperation may be performed in the matrix G. In this case the blockspreading is performed prior to the scrambling operation.

In FIG. 18 a block diagram of embodiments herein is disclosed. The userequipment 10 may alternatively comprise an error correction codingmodule 181, wherein the sequence or block of bits a may be encoded tomake it more robust against transmission errors. The error correctioncoding module 181 may correspond to the error correction coding module111 in FIG. 11. In order to randomize neighbor cell interference cellspecific scrambling with code c may be applied to the possibly errorcorrection encoded block of bits in a bit scrambling module 182. Thescrambled block of bits s is then mapped onto a sequence of complexvalued modulation symbols in a symbol mapping module 183. The modulationsymbols are block spread with a spreading sequence (not shown). The userequipment 10 then transforms e.g. precodes, per DFTS-OFDM symbol, theblock-spread sequence of complex valued modulation symbols, with thematrix G 114 that depends on a DFTS-OFDM symbol index and/or slot index.The user equipment 10 may also comprise a IFFT module 185 and a cyclicprefix generator 186. The block spread modulation symbols, i e the blockspread sequence of complex valued modulation symbols, is modulated andtransmitted over the DFTS-OFDM symbol or within one DFTS-OFDM symbolduration. However, to enable multiplexing of users the scrambled blockof bits s is to be transmitted over several DFTS-OFDM symbols to theradio base station 12.

The matrix G 114 in the DFTS-OFDM modulator 113 may vary with cell IDand/or DFTS-OFDM symbol index/slot/subframe/radio frame number becauseof the scrambling code dependence.

The matrix G may be a product of a diagonal matrix and a DFT matrix.However, instead of a product, we may assume a general matrix G. Torandomize interference matrix G may depend on cell ID and/or DFTS-OFDMsymbol index/slot/subframe/radio frame number. In order to be able todecode the transmitted signal of uplink control information at thereceiver the minimum requirement on G is that its inverse exists.

A simpler receiver may be constructed if matrix G is orthogonal since inthis case its inverse is just the hermitian transpose of matrix G.Depending on the application a low envelope fluctuation of thetransmitted signal of uplink control information, low cubic metric orpeak to average power ratio, may be of interest. In this case thecombination of matrix G and subsequent IFFT operation should result in asignal with low cubic metric.

One such matrix would be a DFT matrix, which rows or columns arecyclically shifted, e.g. assuming M rows, row 1 becomes row n, row 2becomes row (n+1) mod M, and so on. This operation results in a cyclicshift of the subcarriers or mapped complex valued modulation symbols,see FIG. 14 for an illustration. The amount of cyclic shifting or cyclicshift pattern may depend on cell ID and/or DFTS-OFDM symbolindex/slot/subframe/radio frame number. Cyclic shifting of subcarriersor complex valued modulation symbols that depends on cell ID as well as,or, DFTS-OFDM symbol index/slot/subframe/radio frame number randomizesinter-cell interference and mitigates inter-cell interference. Thisimproves inter-cell interference mitigation compared to prior artDFTS-OFDM PUCCH transmissions. The DFT matrix may in some embodiments bethe product of a DFT matrix and a diagonal scrambling matrix.

A general permutation of rows or columns is also possible; however,cubic metric increases in this case.

The techniques disclosed herein enable, e.g. high payload PUCCHtransmissions, in some embodiments. Furthermore, these techniques mayalso provide flexibility to adapt the solution to the required payload.These techniques are also helpful in that they introduce means toimprove inter-cell interference. These means are either scrambling witha scrambling code, selection of a matrix G, and/or cyclic shifting ofmatrix elements with a cyclic shift pattern. The selection of thescrambling code c or cyclic shift pattern may depend on cell ID and/orDFTS-OFDM symbol/slot/subframe/radio frame number in a pseudo randomfashion to randomize inter-cell interference. Furthermore, embodimentsherein allow varying the structure of PUCCH format to trade payloadand/or coding gain and/or inter-cell interference suppression againstmultiplexing capacity.

FIG. 19 is a schematic block diagram depicting an embodiment of atransmission process in the user equipment 10. A block of bitscorresponding to uplink control information is to be transmitted over aradio channel to the radio base station 12. For example, a number ofHARQ feedback bits may be determined by the number of configured cellsand transmission mode, e.g. Component Carrier 1 (CC1), CC3: MIMO, CC2:no MIMO. The block of bits may be error correction encoded in a ForwardError Correction (FEC) module 191. Furthermore, the error correctionencoded block of bits may then be scrambled in a bit scrambling module192, which may correspond to the bit scrambling module 182 in FIG. 18.The user equipment 10 further comprises a number of block modulesMod0-Mod4. Each block module comprises a bit to symbol mapping modulewherein the block of bits is mapped to a sequence of complex valuedmodulation symbols. Furthermore, each block module Mod0-Mod4 comprises ablock spreading module configured to together block spread the sequenceof complex valued modulation symbols with a spreading sequence oc1-oc4,e.g. orthogonal cover to multiplex user equipments. Within each blockmodule the block spreading is just a multiplication by oci, i=0, . . . ,4. The block modules Mod0-Mod4 together block spread the sequence ofcomplex valued modulation symbols with [oc0, oc1, . . . , oc4]. Also,the block spread sequence of complex valued modulation symbols istransformed per DFTS-OFDM symbol, i.e. each segment of the block spreadsequence of complex valued modulation symbols is transformed by applyinga matrix that depends on, i.e. varies with, a DFTS-OFDM symbol indexand/or slot index. This may be performed by first cyclically shiftingeach segment of the block spread sequence of complex valued modulationsymbols, thus performing a pseudo-random cyclic shift to randomizeinter-cell interference. Then each cyclically shifted segment isprocessed, e.g. transformed, in a DFT matrix. The cyclically shifted andDFT transformed segment is then IFFT transformed and the block spreadsequence of complex valued modulation symbols that has been transformedis transmitted over the DFTS-OFDM symbols or within the duration of theDFTS-OFDM symbols.

Reference signals (RS)s are also transmitted according to a pattern overa DFTS-OFDM symbol duration. Each RS is IFFT transformed before beingtransmitted.

Various embodiments herein include methods of encoding and/ortransmitting signalling messages according to the techniques describedabove, in LTE-Advanced or other wireless communication systems. Otherembodiments include user equipments or other wireless nodes configuredto carry out one or more of these methods, including mobile stationsconfigured to encode and/or transmit signalling messages according tothese techniques, and wireless base stations, e.g., e-NodeB's,configured to receive and/or decode signals transmitted according tothese signalling methods. Several of these embodiments may comprise oneor more processing circuits executing stored program instructions forcarrying out the signalling techniques and signalling flows describedherein; those skilled in the art will appreciate that these processingcircuits may comprise one or more microprocessors, microcontrollers, orthe like, executing program instructions stored in one or memorydevices.

Of course, those skilled in the art will appreciate that the inventivetechniques discussed above are not limited to LTE systems or toapparatuses having a physical configuration identical to that suggestedabove, but will appreciate that these techniques may be applied to othertelecommunication systems and/or to other apparatuses.

The method steps in the user equipment 10 for transmitting uplinkcontrol information in time slots in a subframe over a radio channel tothe radio base station 12 according to some general embodiments will nowbe described with reference to a flowchart depicted in FIG. 20. Thesteps do not have to be taken in the order stated below, but may betaken in any suitable order. The radio channel is arranged to carryuplink control information and the user equipment 10 and radio basestation 12 are comprised in a radio communications network. The uplinkcontrol information is comprised in a block of bits. In some embodimentsthe block of bits corresponds to uplink control information andcomprises jointly encoded acknowledgements and non-acknowledgements. Theradio channel may be a PUCCH.

Step 201. The user equipment 10 may in some embodiments, as indicated bythe dashed line, error correction encode the block of bits. For example,the block of bits may be forward error correction processed or similar.

Step 202. The user equipment 10 may in some embodiments, as indicated bythe dashed line, scramble the block of bits before mapping the block ofbits to the sequence of complex valued modulation symbols. Thescrambling process is to reduce inter cell interference and may be cellspecific or similar.

Step 203. The user equipment 10 maps the block of bits to a sequence ofcomplex valued modulation symbols.

Step 204. The user equipment 10 block spreads the sequence of complexvalued modulation symbols across DFTS-OFDM symbols by applying aspreading sequence to the sequence of complex valued modulation symbols,to achieve a block spread sequence of complex valued modulation symbols.

Step 205. The user equipment 10 transforms, per DFTS-OFDM symbol, theblock-spread sequence of complex valued modulation symbols by applying amatrix that depends on a DFTS-OFDM symbol index and/or slot index to theblock-spread sequence of complex valued modulation symbols. In someembodiments, the matrix comprises matrix elements, and the matrixcorresponds to a DFT operation together with a cyclic shift operation ofrows or columns of the matrix elements. In some alternative embodiments,the matrix, that comprises matrix elements, corresponds to a DiscreteFourier Transformation operation together with a scrambling operation ofthe matrix elements.

Step 206. The user equipment 10 may in some embodiments, as indicated bythe dashed line, furtherOFDM modulate, per DFTS-OFDM symbol, the blockspread sequence of complex valued modulation symbols that has beentransformed. For example, the sequence may be transformed in an IFFTprocess and a cyclic prefix may be added in a cyclic prefix process.

Step 207. The user equipment 10 transmits the block spread sequence ofcomplex valued modulation symbols that has been transformed over theradio channel to the radio base station 12. In some embodiment thetransmitting comprises to transmit a first part of the sequence ofcomplex valued modulation symbols in a first time slot and a second partof the sequence of complex valued modulation symbols in a second timeslot.

Depending on whether frequency-hopping at slot boundaries is applied,other variants may be derived.

In some embodiments a method in a terminal for transmitting uplinkcontrol information in a slot in a subframe over a channel to a basestation in a wireless communication system is provided. The uplinkcontrol information may be comprised in a code word. The terminal mapsthe code word to modulation symbols. The terminal then block spreads themodulation symbols across DFTS-OFDM symbols by repeating the modulationsymbols for each DFTS-OFDM symbol and applying a block spreadingsequence of weight factors to the repeated modulation symbols, whereinthe repeated modulation symbols include the modulation symbols to whichthe code word has been mapped, to achieve a respective weighted copy ofthe modulation symbols for each DFTS-OFDM symbol. The terminal thentransforms, in some embodiments by precoding or DFTS-OFDM modulating,for each DFTS-OFDM symbol, the respective weighted copy of themodulation symbols by applying a matrix that depends on a DFTS-OFDMsymbol index and/or slot index to the respective weighted copy of themodulation symbols. The terminal 10 then transmits, on, or in/within,each DFTS-OFDM symbol or symbol duration, the respective weighted copyof the modulation symbols that has been transformed to the base station.In alternative embodiments, the code word may be repeated for eachDFTS-OFDM symbol and then the repeated code words, including the codeword that has been repeated, are mapped to modulation symbols, i e inthese embodiments the repeating and mapping steps of the block spreadingare done in reverse order, and followed by the weighting step.

The channel may be a Physical Uplink Control Channel and the code wordmay be a number of bits. The modulation symbols may be QPSK symbols orBPSK symbols. In some embodiments, the block spreading sequence may bean orthogonal sequence. The step of transforming may in some embodimentscomprise to cyclically shift the matrix, which matrix may be a DiscreteFourier Transform matrix.

To perform the method steps above for transmitting uplink controlinformation in time slots in the subframe over the radio channel to theradio base station 12 the user equipment 10 comprises an arrangementsdepicted in FIG. 21. The radio channel may comprise PUCCH or otheruplink control radio channels and is arranged to carry uplink controlinformation. As stated above, the block of bits may correspond to uplinkcontrol information and comprise jointly encoded acknowledgements andnon-acknowledgements.

In some embodiments the user equipment 10 may comprise an errorcorrection coding circuit 211 configured to error correction encode theblock of bits.

Furthermore, the user equipment may comprise a scrambling circuit 212configured to scramble the block of bits before mapping the block ofbits to the sequence of complex valued modulation symbols.

The user equipment 10 comprises a mapping circuit 213 configured to mapthe block of bits to the sequence of complex valued modulation symbols.

Furthermore, the user equipment 10 comprises a block spreading circuit214 configured to block spread the sequence of complex valued modulationsymbols across DFTS-OFDM symbols by applying a spreading sequence to thesequence of complex valued modulation symbols, thereby achieving a blockspread sequence of complex valued modulation symbols.

The user equipment 10 also comprises a transforming circuit 215configured to transform, per DFTS-OFDM symbol, the block-spread sequenceof complex valued modulation symbols by applying a matrix that dependson a DFTS-OFDM symbol index and/or slot index to the block-spreadsequence of complex valued modulation symbols. The matrix may in someembodiments comprise matrix elements and correspond to a DiscreteFourier Transformation operation together with a cyclic shift operationof rows or columns of the matrix elements. The matrix, that may comprisematrix elements, may correspond to a Discrete Fourier Transformationoperation together with a scrambling operation of the matrix elements.

Additionally, the user equipment 10 comprises a transmitter 217configured to transmit the block spread sequence of complex valuedmodulation symbols that has been transformed over the radio channel tothe radio base station 12. The transmitter 217 may in some embodimentsbe configured to transmit a first part of the sequence of complex valuedmodulation symbols in a first time slot and a second part of thesequence of complex valued modulation symbols in a second time slot.

In some embodiments the user equipment 10 further comprises an OFDMmodulator 216, which is modified or configured to OFDM modulate, perDFTS-OFDM symbol, the block spread sequence of complex valued modulationsymbols that has been transformed. For example, each segment of theblock spread sequence of complex valued modulation symbols within aDFTS-OFDM symbol is transformed by applying the matrix to the segment ofthe block spread sequence of complex valued modulation symbols in thetransforming circuit 215, and then OFDM modulated in the OFDM modulator216 and transmitted within the DFTS-OFDM symbol. The transmitter 217 maybe comprised in the OFDM modulator 216.

The embodiments herein for transmitting uplink control information overa radio channel to the radio base station 12 may be implemented throughone or more processors, such as a processing circuit 218 in the userequipment 10 depicted in FIG. 21, together with computer program codefor performing the functions and/or method steps of the embodimentsherein. The program code mentioned above may also be provided as acomputer program product, for instance in the form of a data carriercarrying computer program code for performing the present solution whenbeing loaded into the user equipment 10. One such carrier may be in theform of a CD ROM disc. It is however feasible with other data carrierssuch as a memory stick. The computer program code may furthermore beprovided as pure program code on a server and downloaded to the userequipment 10.

The user equipment 10 may further comprise a memory 219 configured to beused to store data, spreading sequence, matrix, and application toperform the method when being executed on the user equipment 10 and/orsimilar.

The method steps in the radio base station 12 for receiving uplinkcontrol information in time slots in a subframe over a radio channelfrom the user equipment 10 according to some general embodiments willnow be described with reference to a flowchart depicted in FIG. 22. Thesteps do not have to be taken in the order stated below, but may betaken in any suitable order. The radio channel is arranged to carryuplink control information and the user equipment 10 and radio basestation 12 are comprised in a radio communications network. The uplinkcontrol information is comprised in a block of bits. In some embodimentsthe block of bits corresponds to uplink control information andcomprises jointly encoded acknowledgements and not acknowledgements. Theradio channel may be a PUCCH.

Step 221. The radio base station 12 receives a sequence of complexvalued modulation symbols.

Step 222. The radio base station 12 OFDM demodulates the sequence ofcomplex valued modulation symbols.

Step 223. The radio base station 12 then transforms, per DFTS-OFDMsymbol, the OFDM demodulated sequence of complex valued modulationsymbols by applying a matrix that depends on a DFTS-OFDM symbol indexand/or slot index to the OFDM demodulated sequence of complex valuedmodulation symbols. This matrix may perform/result in the inverseoperation to that of the matrix G in the user equipment 10. The inverseoperation may in some embodiments comprise an Inverse Discrete FourierTransform operation, and the inverse matrix to the matrix G may comprisean Inverse Discrete Fourier Transform matrix.

Step 224. The radio base station 12 also block despreads the sequence ofcomplex valued modulation symbols that has been OFDM demodulated andtransformed, with a despreading sequence, such as an orthogonalsequence.

Step 225. The radio base station 12 maps the despread sequence ofcomplex valued modulation symbols that has been OFDM demodulated andtransformed, to a block of bits representing the uplink controlinformation.

Thus, the radio base station 12 may decode the received uplink controlinformation.

The method may be performed by a radio base station 12. FIG. 23 is ablock diagram of the radio base station 12 for receiving uplink controlinformation in time slots in a subframe over a radio channel from theuser equipment 10. The radio channel is arranged to carry uplink controlinformation.

The radio base station 12 comprises a receiver 231 configured to receivea sequence of complex valued modulation symbols and an OFDM demodulatingcircuit 232 configured to OFDM demodulate the sequence of complex valuedmodulation symbols.

Furthermore, the radio base station 12 comprises a transforming circuit233 configured to transform, per DFTS-OFDM symbol, the OFDM demodulatedsequence of complex valued modulation symbols by applying a matrix thatdepends on a DFTS-OFDM symbol index and/or slot index to the OFDMdemodulated sequence of complex valued modulation symbols. This matrixmay perform/result in the inverse operation to that of the matrix G inthe user equipment 10. The inverse operation may in some embodimentscomprise an Inverse Discrete Fourier Transform operation, and theinverse matrix to the matrix G may comprise an Inverse Discrete FourierTransform matrix.

The radio base station 12 also comprises a block despreading circuit 234configured to block despread the sequence of complex valued modulationsymbols that has been OFDM demodulated and transformed, with adespreading sequence.

Furthermore, the radio base station 12 comprises a mapping circuit 235configured to map the despread sequence of complex valued modulationsymbols that has been OFDM demodulated and transformed, to a block ofbits representing the uplink control information.

The embodiments herein for receiving uplink control information over aradio channel from the user equipment 10 may be implemented through oneor more processors, such as a processing circuit 238 in the radio basestation 12 depicted in FIG. 23, together with computer program code forperforming the functions and/or method steps of the embodiments herein.The program code mentioned above may also be provided as a computerprogram product, for instance in the form of a data carrier carryingcomputer program code for performing the present solution when beingloaded into the radio base station 12. One such carrier may be in theform of a CD ROM disc. It is however feasible with other data carrierssuch as a memory stick. The computer program code may furthermore beprovided as pure program code on a server and downloaded to the radiobase station 12.

The radio base station 12 may further comprise a memory 239 comprisingone or more memory units and configured to be used to store data,spreading sequence, matrix, and application to perform the method whenbeing executed on the radio base station 12 and/or similar.

In the drawings and specification, there have been disclosed exemplaryembodiments herein. However, many variations and modifications may bemade to these embodiments without substantially departing from theprinciples of the embodiments. Accordingly, although specific terms areemployed, they are used in a generic and descriptive sense only and notfor purposes of limitation, the scope of the invention being defined bythe following claims.

1. A method in a user equipment for transmitting uplink controlinformation in time slots of a subframe over a radio channel to a radiobase station, wherein the user equipment and radio base station arecomprised in a radio communications network, wherein the radio channelis configured to carry the uplink control information, wherein theuplink control information is comprised in a block of bits, and whereinthe method comprises: mapping the block of bits to a sequence of complexvalued modulation symbols, block spreading the sequence of complexvalued modulation symbols across Discrete Fourier TransformSpread-Orthogonal Frequency Division Multiplexing (DFTS-OFDM) symbols byapplying a spreading sequence to the sequence of complex valuedmodulation symbols, to achieve a block spread sequence of complex valuedmodulation symbols, transforming, per DFTS-OFDM symbol, the block-spreadsequence of complex valued modulation symbols by applying a matrix thatdepends on at least one of a DFTS-OFDM symbol index and a slot index tothe block-spread sequence of complex valued modulation symbols, andtransmitting the block spread sequence of complex valued modulationsymbols, as transformed, over the radio channel to the radio basestation.